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cssnano-paras20xx

library3.7.3-patch2jsnpmunverified

A modular CSS minifier built on top of PostCSS, version 3.7.3 (patch2). It uses small PostCSS plugins to perform advanced optimizations like custom identifier reduction, z-index rebasing, and adjacent selector merging. Released frequently alongside PostCSS updates. Differentiates from simpler minifiers (e.g., csso, clean-css) by leveraging the PostCSS ecosystem for extensibility and modularity.

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npm install cssnano-paras20xx

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · CSSNANO-PARAS20XX

cssnano-paras20xx

devopsjavascriptv3.7.3-patch2

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

cssnano

✓ import cssnano from 'cssnano'

✗ const cssnano = require('cssnano').default

Default export in ESM; CommonJS requires '.default' if using named export incorrectly.

cssnano (as PostCSS plugin)

✓ postcss([ cssnano() ])

✗ postcss().use(cssnano)

cssnano is a function that returns a plugin, not a plugin object itself.

Options with safe mode

✓ cssnano({ safe: true })

✗ cssnano({ options: { safe: true } })

Options are passed directly to the cssnano function, not nested.

Demonstrates using cssnano as a PostCSS plugin with safe mode enabled to avoid aggressive optimizations.

import postcss from 'postcss'; import cssnano from 'cssnano'; const input = 'h1 { color: red; color: blue; }'; const result = await postcss([ cssnano({ safe: true }) ]).process(input, { from: undefined }); console.log(result.css); // 'h1{color:blue}'

Debug

Known issues

breakingOptions object structure changed – previously `options` wrapper, now flat.

fix

Use `cssnano({ safe: true })` instead of `cssnano({ options: { safe: true } })`.

affects: <3.0

deprecated`options.safe` is deprecated and will be removed in version 4; use `cssnano({ preset: 'safe' })` or configure directly.

fix

Use `cssnano({ preset: 'safe' })` or set specific options.

affects: >=3.0 <4

gotchacssnano modifies `z-index` values globally, which can break stacking contexts when used on partial CSS.

fix

Use `cssnano({ zindex: false })` to disable z-index rebasing.

affects: >=2.0

gotchaAggressive optimizations (default) may merge or remove CSS that appears redundant but is semantically meaningful.

fix

Enable safe mode or explicitly disable individual optimizations.

affects: >=2.0 <4

breakingcssnano v4 changes default presets and removes many options; migration required.

fix

Consult migration guide; use `cssnano({ preset: 'default' })` and review breaking changes.

affects: >=4.0

Errors

Common errors & fixes

TypeError: cssnano is not a function

Importing cssnano as a default export but using it incorrectly (e.g., without calling it).

fix

Ensure you call cssnano() to get the plugin: `postcss([ cssnano() ])`.

Options were removed in cssnano 4.0. Use presets instead.

Using old options like `safe` or `zindex` directly in v4.

fix

Use `cssnano({ preset: 'safe' })` or configure via `preset`.

Cannot find module 'cssnano'

cssnano is not installed or the import path is wrong.

fix

Run `npm install cssnano --save-dev` and import using `import cssnano from 'cssnano'`.

Upgrade

Version history

3.7.3-patch2latest on npm

Audit

Dependencies

postcssrequiredCore dependency – cssnano runs as a PostCSS plugin

Agent activity

4 hits · last 30 days

node

Resources

githubhttps://github.com/ben-eb/cssnano ↗

packagecssnano-paras20xx ↗

homepagehttps://github.com/ben-eb/cssnano ↗